Do a round of copyediting

We had been meaning to do some final copyediting prior to this RFC
being merged, so let's do that.  In addition to making the text a bit
more regular and precise, fixing some minor errors, removing outdated
information, and adding references between sections, we've tried to
"tighten it up" a bit where possible.  We've been careful to not
change anything of semantic significance or otherwise of significance
to the consensus.

Author: traviscross